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[Bug target/53772] New: Failed to combine load and jump on vtable
- From: "hjl.tools at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Mon, 25 Jun 2012 21:59:22 +0000
- Subject: [Bug target/53772] New: Failed to combine load and jump on vtable
- Auto-submitted: auto-generated
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53772
Bug #: 53772
Summary: Failed to combine load and jump on vtable
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: hjl.tools@gmail.com
CC: areg.melikadamyan@gmail.com, ubizjak@gmail.com
Target: x86-64
[hjl@gnu-6 tmp]$ cat v.cc
struct Foo { virtual void f(); }; void f(Foo *f) { f->f(); }
[hjl@gnu-6 tmp]$ /opt/llvm/bin/clang -S -m64 -O2 -o clang64.s v.cc
[hjl@gnu-6 tmp]$ cat clang64.s
.file "v.cc"
.text
.globl _Z1fP3Foo
.align 16, 0x90
.type _Z1fP3Foo,@function
_Z1fP3Foo: # @_Z1fP3Foo
.cfi_startproc
# BB#0: # %entry
movq (%rdi), %rax
jmpq *(%rax) # TAILCALL
.Ltmp0:
.size _Z1fP3Foo, .Ltmp0-_Z1fP3Foo
.cfi_endproc
.section ".note.GNU-stack","",@progbits
[hjl@gnu-6 tmp]$ /usr/gcc-4.7.2-x32/bin/gcc -S -O2 -m64 v.cc -o gcc64.s
[hjl@gnu-6 tmp]$ cat gcc64.s
.file "v.cc"
.text
.p2align 4,,15
.globl _Z1fP3Foo
.type _Z1fP3Foo, @function
_Z1fP3Foo:
.LFB0:
.cfi_startproc
movq (%rdi), %rax
movq (%rax), %rax
jmp *%rax
.cfi_endproc
.LFE0:
.size _Z1fP3Foo, .-_Z1fP3Foo
.ident "GCC: (GNU) 4.7.2 20120622 (prerelease)"
.section .note.GNU-stack,"",@progbits
[hjl@gnu-6 tmp]$